This disclosure relates to an electrode assembly and a method for manufacturing said assembly.
According to Japanese Laid-Open Patent Publication No. 9-120836, describing a secondary battery, an electrode assembly and electrolyte solution are sealed in an inside of a case. The electrode assembly includes positive electrode plates and negative electrode plates that are stacked in an alternating manner wherein each of the positive electrode plates is enveloped by a separator. The electrolyte solution is filled in the case when a secondary battery is new. Accordingly, the electrolyte solution is filled around active material layers of the positive electrode plates and the negative electrode plates. Over time, the electrolyte solution is reduced with the use of the secondary battery due to electrolysis or evaporation. As a result, the active material layers of the positive electrode plates and the negative electrode plates are exposed from the electrolyte solution as the electrolyte solution is reduced. An electrolyte solution is built up around the exposed active material layers. The electrolyte solution immersed in the active material layers stays around the active material layers due to surface tension so as to form the built up electrolyte solution. The electrolyte solution immersed in the active material layers stays around the active material layers due to surface tension so as to form this electrolyte sump. The active material layers expand and contract while the secondary battery is charged and discharged. In accordance with this expansion and contraction, the electrolyte solution flows out and back between the active material layers and the built up electrolyte solution. The electrolyte solution is supplied to the active material layers as the electrolyte solution returned to the active material layers. The active material layers are impregnated with the electrolyte solution so as not to dry.
The Japanese Laid-Open Patent Publication No. 9-120836 does not disclose a specific structure for promoting the electrolyte solution to be supplied into each active material layer. It does not disclose a specific structure for suppressing uneven impregnation of electrolyte solution in a laminating direction of positive electrode plates and negative electrode plates. It does not disclose a specific structure for ensuring sufficient capacity for the active materials of each of the positive and negative electrode plates.